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If forced (at gunpoint)to come up with a fast
explanation the sail on Spinosaurus, thermal
adaptation (heat radiator) would be my first
2nd....predator avoidance 3rd. Never would have
thought of shade, which is why it's fun. 02 iso
asymmetries?? "limb"? Ya think? Still fun though.
--- Renato Santos <firstname.lastname@example.org> wrote:
> > Demetrios Vital wrote:
> > >How plausible is this behavior considering the
> > environs of
> > >Spinosaurus? Are there other species of fish
> > congregate in
> > >shade, or other predators that use their shadow
> > hunt?
> > Well, I'm not all that knowledgeable about the
> > paleoenvironment in that
> > region of Africa (Baharija Fm.), except that it
> > an estuary.
> > *Spinosaurus* has as far as we know piscivorous
> > adaptations; I'm just
> > proposing a modus operandi for the creature's
> > feeding habits based on extant
> > creatures that approximate its niche (if there are
> > any). In fact,
> > *Spinosaurus* might as well had brightly colored
> > feet as some herons do to
> > scare off fish as it waded ;-)
> > Being a big animal and presumably catching big
> > in murky waters, I think
> > this way of fishing provided two benefits: fish
> > naturally attracted to
> > shades as they tend to denote thick vegetation and
> > rocky areas where
> > land-bound and aerial predators are less likely to
> > attack them (at least
> > that's what I hear on wildlife shows); the animal
> > could use its shade as a
> > way to diminish the glare the water's surface
> > produces thus being able to
> > see the fish more clearly.
> > >Really interesting speculation. Is this even
> > remotely provable?
> > If we had an generous amount of fossil evidence we
> > could look at asymmetries
> > in oxygen isotope ratios on the ribs or each side
> > the neurapophyses as
> > these would be exposed to diferent temperatures
> > perhaps even
> > histological evidence that shows how these
> > temperature differences affected
> > the bone. But this would only be valid if the
> > used consistently the
> > same side of the sail to produce shade. To prove
> > that the animal waded
> > regularly one could compare the oxygen isotope
> > ratios on the feet and leg to
> > the ones on for example the pubic bones, with
> > obviously a calibration chart
> > with results from extant waders, extinct waders
> > non-waders of each type.
> > I am perhaps going out on a limb here but it would
> > be interesting if this
> > could be done even on an academic standpoint.
> > Renato Santos
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